The key stage 1-2 (KS1-2) progress measure is a value added (VA) measure,

VA involves comparing a pupil’s attainment score at KS2 to the average score for pupils with similar prior attainment. There are a few myths we need to bust first, before we continue:

- We do not need data in the same format at either end of the measure to calculate VA. Currently we have KS1 (sub)levels at the beginning and KS2 scaled scores at the end. These data are not in the same format. We needed compatible data for the levels of progress measure but not for VA. This misconception is a hangover from levels, and it’s something that is better understood in secondary schools where they have KS2 scores at one end and GCSE results at the other.
- We do not even need the same subjects at either end. Again, this is better understood in secondary schools, where the baseline comprises KS2 scores in reading and maths (note: no writing) and the end point is any GCSE the student sits. VA can be measured from KS2 test scores in reading and maths to GCSE result in Russian or Art, for example.
- KS1-2 VA has nothing to do with that magic expected standard score of 100. Plenty of pupils get positive progress scores at KS2 without achieving a score of 100 in KS2 tests. They just need to exceed the national average score of pupils with the same prior attainment, and scoring 92 might be enough, depending on start point. And pupils that achieved 2b at KS1 (often referred to as ‘expected’ in old money) do not have to achieve 100 to make ‘good’ progress; in 2017 they had to exceed 102!

Each pupil’s KS1 result – their prior attainment or start point – is therefore crucial to this process. Each p-scale, level and sublevel in reading, writing and maths at KS1 has a point value, which enables the DfE to calculate a KS1 average point score (APS) across the three subjects for every child that has a KS1 result (note: pupils without a KS1 result are excluded from progress measures). Their KS1 APS is then used to place pupils into a prior attainment group (PAG), of which currently we have 24, ranging from pupils that were on p-scales at KS1 (pupils with SEND) up to pupils that were Level 3 in all subjects. There is even a PAG for pupils that were level 4 at KS1, but there aren’t many pupils in that group.

All pupils with KS1 results are therefore slotted into PAGs alongside thousands of other pupils nationally. The DfE then take in all the KS2 test scores and calculate the average KS2 score for each PAG. Let’s look at two examples:

- We have two pupils in a class that have KS1 prior attainment of 16 APS (2b in reading and writing and 2a in maths at KS1). They are placed into the same PAG as thousands of other children nationally with 16 APS at KS1. The DfE take in all the thousands of test scores for all the pupils in this PAG and calculate the average score, which for this PAG is 105 (note: in reality benchmarks are to 2 decimal places e.g. 104.88). 105 therefore becomes the benchmark for this group. Our two pupils scored 108 and 101 in their KS2 tests and both have met the expected standard. However, only one pupil has a positive progress score. The pupil scoring 108 has beaten the national benchmark by 3 whilst the other has fallen short by 4. These pupils’ VA scores are therefore +3 and -4 respectively.

- We have two other pupils in our class who have KS1 prior attainment of 10 APS (2c in reading and Level 1 in writing and maths). They are in the same PAG as thousands of other children nationally with 10 APS at KS1. The DfE calculate the KS2 average score for this PAG to be 95, and this becomes the benchmark for this group. Our two pupils scored 98 and 88 in their KS2 tests, which means that one pupil has beaten the national benchmark by 3 whilst the other has fallen short by 7. These pupils’ VA scores are therefore +3 and -7 respectively.

This process is repeated for each pupil that has a KS1 result. All pupils are placed into PAGs and their scores in KS2 tests are compared to the national average score (the benchmark) for pupils in the same PAG. If a pupil beats the benchmark, they have a positive progress score; if they fall short, their progress score is negative. Page 17-18 of the primary accountability guidance has a table of all PAGs with their corresponding KS2 benchmarks in reading, writing and maths.